In the thermal analysis, material characteristics are investigated by means of a sample from the respective material as a function of the temperature. A correct thermometry, that is, a correct measuring of the temperature of the sample, thus plays an important role.
Temperature sensors, e.g. in the form of thermal elements or electrical resistance thermometers, which can be arranged in thermal contact to the sample, e.g., so as to measure the temperature of the sample, are known from the prior art for this purpose.
This measuring, however, is more or less error-prone depending on the temperature program, that is, the change of the sample temperature provided during the thermal analysis, because the temperature sensor does not measure the temperature in the interior of the sample, but on an edge of the sample.
This measuring error is even more significant for temperature sensors (which are used in many cases), which cannot be arranged in direct contact to the sample, but which are instead arranged adjacent to the sample, thus spatially separated therefrom, inside a temperable sample chamber.
This problem can be reduced significantly by means of a suitable “calibration” of the used temperature sensor or of the temperature measuring device formed therewith, respectively. For such a calibration, provision can be made, e.g., to measure the temperature of one or a plurality of samples, which melt in response to temperatures, which are known in each case, in the course of a temperature program in the respective device for the thermal analysis, so as to then calibrate the temperature measuring device or the temperature sensor, respectively, by comparing the measured melting temperatures to the melting temperatures, which are known (e.g. from the literature).
It is a disadvantage, however, that such a calibration of the temperature measuring device is relatively extensive. In spite of the calibration, the measured temperature is also not necessarily representative of the average sample temperature in the sample interior, because more or less large temperature gradients can be present in the sample, depending on the temperature program. A further disadvantage can be that the calibration is no longer correct and a systematic error occurs in the temperature measuring, when changing the position of the temperature sensor even only slightly.
In the case of the known thermometry in the context of a thermal analysis, whether with or without calibration of the above-described type, it is further disadvantageous that many temperature sensors, such as, e.g., thermal elements and resistance thermometers, are oftentimes not stable over a long period of time, but change their characteristics over time due to aging and/or contamination.